Croatia is to demand Greece stop moving refugees coming from the Middle East on to the rest of Europe.

EU interior ministers are to meet on Tuesday in an attempt to find a solution to Europe's biggest migrant crisis since World War Two, with almost half a million asylum seekers reaching its territory this year.

"The flow of migrants from Greece must be stopped. I will seek that at tomorrow's meeting of EU interior ministers," Croatian Interior Minister Ranko Ostojic said.

Mr Ostojic told reporters at the Opatovac camp where migrants are being housed near the eastern town of Tovarnik.

"It is absolutely unacceptable to have Greece emptying its refugee camps and sending people towards Croatia via Macedonia and Serbia," Ostojic added.

Hungarian MPs have approved legislation this afternoon allowing the government to send troops to help police manage the migration crisis.

A refugee boy plays a violin as hundreds of migrants camp in Turkey on the western border with Greece and Bulgaria Credit: Emrah Gurel

The bill lets soldiers carry out many of the same tasks as police, such as checking ID, detaining suspects and controlling the flow of traffic at the borders.

While the soldiers will carry weapons, Hungarian officials vowed that the use of force would be only a last resort.

Defence Minister Istvan Simicsko said earlier that "you truly can't answer a slap with a rocket".

Before the vote, Prime Minister Viktor Orban said that allowing soldiers to help police would ensure Hungary can defend its borders with Serbia, Croatia and Slovenia, from where migrants have been entering on their way to Germany and other Western nations in the European Union.

The Opatovac refugee camp has 200 tents, each with a capacity of housing 24 people Credit: STRINGER (Getty Images)

Around 29,000 people, mostly from Syria, have arrived in Croatia from Serbia in the past week after trekking northwards through the Balkans from Greece en route to wealthier country in the west and north of the European Union.

Croatia is a member of the EU but not part of its Schengen zone of borderless travel.

A Syrian refugee carries his child at a beach on the Greek island of Lesbos after crossing part of the Aegean Sea from the Turkish coast Credit: Yannis Behrakis

Greece has been the first point of entry to the EU for many migrants as it borders Turkey, to which millions have fled from wars in neighbouring Syria and Iraq, but says it cannot cope with the influx given its small size and severe financial woes.

An official of the UN refugee agency, UNHCR, told Reuters there were currently around 2,000 people inside the Opatovac camp, a fenced former industrial plant where around 150 olive-coloured, military-style tents have been set up.

A migrant woman carrying her child arrives with other migrants and refugees to a newly erected refugee camp in the Croatian town of Opatovac, 20 kms from Tovarnik, on September 20, 2015. The camp has 200 tents, each with a capacity of housing 24 people. Migrants are still mostly gathered on Croatia's main border crossings with Slovenia, seeking transit through Slovenian territory in their bid to travel to northern Europe. AFP PHOTO / STRINGERSTRINGER/AFP/Getty Images

"On the average there are around 100 people entering (Croatia) per hour," UNHCR spokesman Babar Baloch said.

"Of course, inflow and outflow must be balanced or (the camp) will become overcrowded... This of course depends on the number of people arriving from Serbia," he said.

Ahead of tomorrow’s meeting, foreign ministers from four eastern European countries are meeting on Monday to discuss the migrant influx amid continuing divisions.

Despite Germany and France wanting migrants to be shared out more evenly across the EU, Poland, Hungary, the Czech Republic and Slovakia remain strongly opposed to accepting obligatory quotas.

Divisions among European states were illustrated by French President Francois Hollande, who said that in the EU "no-one can be exempt" from taking in people with the right to asylum.

Eastern European countries are stressing the need to protect the EU's external borders and distinguish between economic migrants and refugees.

Polish foreign minister Grzegorz Schetyna said his country would be willing to accept more refugees on “a voluntary basis than those stipulated by the compulsory quotas proposed by the European Commission.”

In an opinion piece in the Gazeta Wyborcza daily, he wrote: “Poland is able to take in more refugees… but for this to happen, comprehensive and effective changes must be made by the European Union and its member states on organising political asylum and migration,” he added.

“We need to strike the right balance between helping those in need and guaranteeing the security of our citizens.”

Thousands more migrants entered Austria over the weekend and more are expected to arrive via Hungary on Monday.